n = int(input())
s = input()
rs = s.count('R')
oks = s[:rs].count('R')
print(rs - oks) n = int(input()) n int(input()) int input() input s = input() s input() input rs = s.count('R') rs s.count('R') s.count s count 'R' oks = s[:rs].count('R') oks s[:rs].count('R') [:rs].count [:rs] s :rs rs count 'R' print(rs - oks) print rs - oks rs oks rs = s.count('R') s.count('R') rs n = int(input()) int(input()) n s = input() input() s oks = s[:rs].count('R') s[:rs].count('R') oks
n = int(input())
s = input()
rs = s.count('R')
oks = s[:rs].count('R')
print(rs - oks)